As for translation, I can tell the meaning of each character, 快：fast 联：link 乐：happy 界：scope.

But I cannot tell the true meaning of all them together, may be its a name of a organization.

Precisely, and the Japanese use Chinese characters which is what the article explains. Good to have you here gxjade. I have worked for a Japanese company for 20 years, so I would assume from what you are saying that bunching the meanings of the characters together would basically mean the use of this ball in a round would be fast and give happy results. Being an illegal ball seems to be unspoken I guess as it's assumed no one is supposed to know that unless they already recognize it.